Inflight entertainment (IFE) systems have evolved significantly over the last 25 years. Prior to 1978, IFE systems consisted of audio-only systems. In 1978, Bell and Howell (Avicom Division) introduced a group viewing video system based on VHS tapes. In 1988, Airvision introduced the first in-seat video system allowing passengers to choose among several channels of broadcast video. In 1997, Swissair installed the first interactive video on demand (VOD) system. Currently, many IFE systems provide VOD with full digital video disc (DVD)-like passenger controls.
Most IFE systems are head end centric. FIG. 1 illustrates a legacy head end centric IFE system. The left side of the figure shows components that are found at the head end of the system. The right side of the figure shows components that are found at the passenger seats. The middle section of the figure shows components that are found between the head end and the seat end. These intermediate components are area distribution boxes (ADBs) or may be a combination of ADBs and zone interface units (ZIUs). The main purpose of the ADBs and ZIUs is to fan-out distribution of IFE system data from the head end to the seat end. Typically, ADBs connect to seat electronics boxes (SEBs) within each seat column, and each SEB is in turn connected to multiple video display units (VDUs) and passenger control units (PCUs) of a given seat group. An SEB may also distribute data to an SEB of an adjacent seat group in the same seat column. Alternatively, an ADB may be directly connected to VDUs and/or PCUs.
A more recent head end centric IFE system is shown in FIG. 2. This fiber optic head end centric IFE system leverages terrestrial VOD hardware and software, is implemented on avionics ruggedized militarized commercial off-the-shelf hardware and is packaged to minimize the number of distinct line replaceable units (LRUs) not only in a single aircraft but across an airline's entire fleet of aircraft (e.g., regional jets to jumbo jets). Head end servers and switches are integrated into server-switch units which are directly coupled over fiber to VDUs at the seat end. Serialized versions of this IFE system can be deployed to reduce fiber requirements.
In head end centric IFE systems of any flavor, the seat end equipment accesses selected prerecorded video programs (e.g., movies, television shows, video games, etc.) from the head end equipment “on demand” during the flight by sending program requests that are fulfilled by the head end equipment. In order for these IFE systems to remain fully operational, the head end equipment, distribution system and seat end equipment must all remain operational. Moreover, if the head end equipment or the distribution system becomes inoperable during the flight, the entire IFE system goes down. Unfortunately, this is a fairly common occurrence in many deployed head end centric IFE systems. To address these problems, seat end centric architectures have been proposed.
In proposed seat end centric IFE systems, such as the one illustrated in FIG. 3, seat end equipment hosts a complete library of prerecorded video programs, either within SEBs or VDUs. The head end equipment and the distribution system are used primarily for preloading the complete video library onto the seat end equipment. The IFE system remains operational during the flight as long as the seat end equipment remains powered, eliminating the risk that the IFE system will become inoperable in flight due to a head end equipment or distribution system failure. However, seat end centric IFE systems have the major drawback that the entire video catalog must be replicated for each seat (typically 200 to 500 seats) or at least each seat group, whereas in head end centric IFE systems replication is generally only performed a few times on head end equipment for the sake of redundancy. Therefore, proposed seat end centric IFE systems require far more storage capacity and loading time than head end centric IFE systems.
What is needed is an IFE system that continues in-flight operation through head end or distribution system failures, but without requiring the large multipliers in storage capacity and loading times of proposed seat centric IFE systems.